The Center for Quantitative Cell Analysis of The Pennsylvania State University seeks funds to purchase a state-of-the-art bench top flow cytometer. The Center is one of the Shared Technology Facilities in the Life Sciences Consortium, providing services for the entire University Park campus. Our existing instrument for flow cytometry (a Coulter EPICS 753) is used to capacity and has become increasingly unreliable due to increased maintenance time. We seek an additional flow cytometer (Becton Dickinson FACSCalibur) to: (a) complete about 50% of our current analyses at lower cost to the user's R01 project; (b) free the existing instrument for those demanding multi-laser or sorting capabilities; (C) provide reliable, rapid, multi-parameter analysis to all users. Eight different investigators will use the new cytometer for over 30 hr/wk.